LPRF Spectrum Indicator

Part of my summer internship at Texas Instruments LPRF in 2009 was to develop a spectrum analyzer using the CC2511 and CC1111 as a low cost ($49 or $99 depending on what hardware is needed) alternative to the expensive professional spectrum analyzers out there. This resulted in the LPRF Spectrum Indicator, with the name Indicator chosen to emphasize the inaccuracy of the measurements, which you can find below. Although not perfect in any ways, this little tool can prove worthy for many RF developers out there.

For the CC2511it supports the entire 2.4 GHz ISM band and for the CC1111 it supports 877-973 MHz. The PC side was developed using Qt (http://qt.nokia.com/).

Although I’m not considering a lot more development on this, questions, suggestions for improvements or general comments are more than welcome!Want to develop this further? Feel free to post it here on the community. Known issues and improvements to be made are:

There seems to be an offset of 1-4 khz per channel, to the real frequency. Thus, a known peak at 2440 MHz will have an offset of around 150-500kHz when this accords to channel 150 (a little right of the center of the plot). This could be verified by applying a known signal then move the plot so that this peak is drawn at different positions in the plot. At the far left the frequency is correct.

Suggested solution:Find the connection, a mathematical expression of the offset, and compensate when filling the x-axis, GraphPlot::setTraceData().

Start Frequency - RF bandwidth - Channel Spacing There are only a discrete number of values valid for the above mutually dependent variables. When the user interacts through zooming, or direct control through the advanced menu, these values are set to the closest valid value in DataManagement. Currently there are internal function calls within DataManagement to keep dependencies valid, as well as signals sent back to the user through adjustments in GraphPlot. These internal calls and signals have a structure which should be improved. The adjustments finally applied might not always appear logical to the user. For example, centering on cursor, as well as zooming, does not always give the intuitive result. I've tried to encapsulate as much as possible, but might have ended up with a too complicated structure.

Suggested solution:Turn the requested change from user into one signal, with only one response. Or keep essential variables, such as Start frequency - End frequency - Channel spacing shared between GUI and DataManagement.

In TraceControl::MaxHold when zooming, the first set of samples is not captured by the break argument. This might be because the x-axis is altered, but not fed with new RSSI values. This causes an eventual peak to remain until it is no longer amongst the last TraceControl::m_nofMaxHoldSamples. You'll notice this when zooming on a peak. The problem is that this peak is no shown in the right place.

Suggested solution:

Only pdf is currently supported as an export format.

Suggested solution:Change the GraphPlot::export() to find the fileformat from the incoming file name. According to this, do the exporting, f.ex. use QSvgGenerator.

A curve's properties can not be changed after being chosen. That is, the properties set when adding a trace.

Suggested solution:Include a button calling the OptionsCurve dialog.

It should be automatically found which virtual serial port the CC2511 is located at.

Suggested solution:--

Hope you like this.

Enjoy!

Regards,Torbjørn

Best regards,

Torbjorn

Helps us tracking and improving the quality of our support to the community:

if you were satisfied with the answer and of the support, could you please click on 'Verify this post'?

you did an excellent job. I know it is not easy to manage system
architecture, signal processing and computing in a single project.

I am new to ZigBee, I work on a project whose goal is to restore the physical signal at the receiver.
This work is done by manipulating the MSP430F2618 to program the
CC2520, to extract the received signal before the decision on the samples
is made.

I'd like to know if you got to work on this idea to recover the signal, and if you can help me. If you have any idea to suggest it to me.

Can you send to me your probation report and the documents that helped you with your project.Thank you

When I checked the official release, I noticed that the frequency span of the CC1111 was changed upward. The most interesting ISM bands are around 863-870MHz (Europe) and 902-928MHz) in the US, please make sure that those frequency bands are covered.

Thanks for sharing this with us. I just got it all working and it looks like it will be very handy for us working on LPW development projects, even though we have a couple of real spectrum analyzers. Sometimes it's useful to have this little spectrum indicator at our desks without having to bring the big spectrum analyzer over from the lab.

I am wondering if you are making the firmware source code available somewhere? I don't see it in any of the links you posted above.

All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.

Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Terms of Use of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Terms of Use of this site. TI, its suppliers and providers of content reserve the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.